The present disclosure relates to a rotor and a brushless motor.
A rotor having a so-called Lundell-type structure using a permanent magnet field is one type of a rotor for a brushless motor (for example, refer to Japanese Laid-Open Patent Publication No. 2012-115085 and Japanese Laid-Open Utility Model Publication No. 5-43749). Such a rotor includes two rotor cores that are combined with each other. Each rotor core includes a plurality of claw-shaped magnetic pole portions arranged in the circumferential direction. A field magnet is arranged between the rotor cores and magnetized in the axial direction. The field magnet functions claw-shaped magnetic pole portions alternately as different magnetic poles.
In the brushless motor, the rotation position (angle) of the rotor is detected and drive current is supplied to the windings of a stator in accordance with the rotation position. This generates a rotating field, and the rotating field rotates and drives the rotor.
In a structure for detecting the rotation position of a rotor, for example, a sensor magnet may be arranged on a rotor core, and a magnetic sensor may be arranged on a stator side to detect the magnetic field of the sensor magnet.
In such a brushless motor, it is desirable that the magnetic sensor accurately detect the rotation position (angle) of the rotor.